Vitis HLS Memory Layout Model - 2023.2 English

Vitis High-Level Synthesis User Guide (UG1399)

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2023.2 English

The Vitis application acceleration development flow provides a framework for developing and delivering FPGA accelerated applications using standard programming languages for both software and hardware components. The software component, or host program, is developed using C/C++ to run on x86 or embedded processors, with OpenCL/ Native XRT API calls to manage run time interactions with the accelerator. The hardware component, or kernel (that runs on the actual FPGA card/platform), can be developed using C/C++, OpenCL C, or RTL. The Vitis software platform promotes concurrent development and test of the hardware and software elements of a heterogeneous application. Due to this, the software program that runs on the host computer needs to communicate with the acceleration kernel that runs on the FPGA hardware model using well-defined interfaces and protocols. As a result, it becomes important to define the exact memory model that is used so that the data that is being read/written can be correctly processed. The memory model defines the way data is arranged and accessed in computer memory. It consists of two separate but related issues: data alignment and data structure padding. In addition, the Vitis HLS compiler supports the specification of special attributes (and pragmas) to change the default data alignment and data structure padding rules.